Full threat to British wildlife is laid bare in a new report showing up to half the country could be licensed for shale gas extraction.

The threat posed to wildlife by fracking is laid bare today as a new report identifies vast swathes of environmentally sensitive land across Britain that could be excavated for shale oil and gas.

The land covers tens of thousands of square kilometres and includes thousands of sites such as Morecombe Bay in the North West, one of the most important areas in Europe for hosting wintering birds, as well as the North York Moors and the Thames Estuary.

An alliance of wildlife groups including RSPB and the National Trust is calling on the government to establish “frack-free zones” across the country to protect areas of particular environmental importance.

The proposed zones would cover a total area of about 42,000 square kilometres – or about 18 per cent of Britain. Some of them are already under threat from licences previously granted to fracking companies, some could be put at risk from licences due to be auctioned in a giant licensing round this summer, while others are not currently in any danger. The so-called 14th licensing round in the summer potentially covers about 40 per cent of Britain, although experts expect only a fraction of this will end up being licensed – at least this time round, as gas companies initially compete for the most attractive locations.

The zones cover all protected wildlife areas, nature reserves and national parks. The alliance is also calling for full environmental assessments to be carried out for each drilling proposal and for the shale gas industry to pay the costs of its regulation and any pollution clean-ups.

Martin Harper, RSPB’s conservation director, said: “The Prime Minister has been a great advocate for the shale gas industry. He has said we have the strongest environmental controls in this country and nothing will go ahead if there are environmental dangers.”

Some 481 environmentally sensitive sites fall within areas currently under licence, meaning that oil and gas companies are already free to develop the site, although any development will be contingent on finding commercially-viable quantities of oil or gas to extract. A further 2,676 sites fall within areas that will come up for auction in the summer licensing round.